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I will be dropping off a 327 "870" block this week.
My main goal is to have the block checked for cracks before I decide the direction to take the rebuild.
First things I want checked are the following:
1. Magged for soundness
2. Check the bores for taper
Engine is 30 over now and there is no ridge. Hope it can stay but prepared to go 40 over if need to. I do plan on using forged pistons whichever way I go.
Any other suggestions on the initial checks I should do?
Once block has a clean bill of health I will be looking for the next steps.
Seriously considering making it a 350 with Trick Flow heads but dressing it as a L79 as I have everything needed for that.
Does your block have matching numbers (VIN derivative, build date and engine type)? If so, make it clear to the shop they are not to touch them (a good shop should know).
I would have the block dipped/cleaned (makes sure all the passages get the gunk out), and all the freeze plugs and oil galley plugs removed and replaced, plus the water jacket drain plugs removed and replaced.
Besides having the bores checked, I would have the shop measure the crank line bore and the block deck heights.
If the block checks out good, I would have new cam bearings installed (indexed to the oil galleries, of course).
No....not a matching numbers. Wish it was but original block was pulled by second owner many years ago and gave away. I bought this from a forum member and now time to get it ready.
No.....the engine sat for way too long without proper prep. I figured as much so I had no surprises really. Planned to do it this way all along.
I figured the sum of just parts was worth the price of admission as long as the block passes inspection.
The block was dated C 12 5 and the 2.02 heads are dated C 10 5 and C 12 5 as well. If I go with the trick flow heads I am sure someone will want these heads.
Did you measure deck clearance before you disassembled the block? You need those numbers to manage the compression ratio. If not have the machine shop measure deck height. Nominal is 9.025". which should yield .025" deck clearance with OE compression height pistons.
Deck clearance is the biggest variable that affects final compression ratio.
My DESIRED way to go with a 327 is to build it with a 350 crank (additional 1/4in stroke), which is TOO EASY to be done by any good machine shop.
This is done by turning down the mains of a 350 crank and slightly reducing the diameter of the flange at the rear of crank. On a 350 crank, that flange is slightly large than the flange on a 327 crank, and it has to be reduced to fit into the groove in the block and rear main cap. That's all that has to be done to drop a 350 crank into a small journal 327 block. Retain the large journals for the rods and use 350 rods. Then just build is as any 350 would be built.
Also, on ANY small journal block, I like to have the bolt holes for the main cap bolts modified to 69-later bolt holes and use the longer 350 style main bolts (as below).
I am finishing the machine work on one today. I always remove this plug and all of the rest on any sbc. On the early SBCs it's not as easy because this a solid plug. But the importance of removing this is this is the main oil passage. Without opening it you cannot thoroughly clean it. I drill and tap the plug and pull it out. Then I'll just make a new one and drive it back in.
Did you measure deck clearance before you disassembled the block? You need those numbers to manage the compression ratio. If not have the machine shop measure deck height. Nominal is 9.025". which should yield .025" deck clearance with OE compression height pistons.
Deck clearance is the biggest variable that affects final compression ratio.
Duke
No sir...
Did not. Should have but hoping the machine shop will do that as I will be buying new pistons as well as new rods. I hope to be able to run 91 non ethanol as a normal basis so I will have to rely on them to calculate the compression ratio.
Later this week I will throw up some pics of the pistons that I pulled out. Kinda some wierd wear pattern in my opinion but it could be normal. Just don't recall seeing wear like this. The block still has a significant amount of cross hatch in the cylinders.
[QUOTE=DZAUTO;1599635977]My DESIRED way to go with a 327 is to build it with a 350 crank (additional 1/4in stroke), which is TOO EASY to be done by any good machine shop.
This is done by turning down the mains of a 350 crank and slightly reducing the diameter of the flange at the rear of crank. On a 350 crank, that flange is slightly large than the flange on a 327 crank, and it has to be reduced to fit into the groove in the block and rear main cap. That's all that has to be done to drop a 350 crank into a small journal 327 block. Retain the large journals for the rods and use 350 rods. Then just build is as any 350 would be built.
Also, on ANY small journal block, I like to have the bolt holes for the main cap bolts modified to 69-later bolt holes and use the longer 350 style main bolts (as below). [/Q
DZ
I have read many articles and yours have been some as well. I had already planned to have the discussion of turning down a lg 350 crank to acheive my desires. I really would love to make it a possible 383 but I know it is sorta iffy with the current block and presents some challenges.
I am finishing the machine work on one today. I always remove this plug and all of the rest on any sbc. On the early SBCs it's not as easy because this a solid plug. But the importance of removing this is this is the main oil passage. Without opening it you cannot thoroughly clean it. I drill and tap the plug and pull it out. Then I'll just make a new one and drive it back in.
HMMM....
Wondering if I should go ahead and pull this one out myself before taking them the block. I have the tools to do it. I am sure they can make a replacement when the time comes or could the block be tapped for a allen head screw to go back in it's place?
Thanks
Its an odd ball size. They can tap it 1/4" npt further in or 3/8" npt on the area you see. I'm just going to make a plug. Directly above the oil filter there is a 1/2" press in plug I take it out as well and thread it.
I took a few photos tonight. I am sure the machine will give an opinion but wondering what some of you think about this cylinder wear. Could be normal as each cylinder shoes the same pattern.
I also included some pics of the pistons, while they look good they do seems to have a stipple type pattern on the skirt. Don't ever remember seeing this before, but it has been many many years since I have done any of this type work so I am learning again.
I have read many articles and yours have been some as well. I had already planned to have the discussion of turning down a lg 350 crank to acheive my desires. I really would love to make it a possible 383 but I know it is sorta iffy with the current block and presents some challenges.
Thanks for the heads up.
I did not mention building a 383 from an early, small journal 327 block, but I have built one and others as well have done it.
There are basically 2 ways to go to build a 383 from a small journal 327 block.
ONE
Line bore the block to large journal (350) specs. This will of course require cutting new notches for the main bearings (tangs on 350 bearings are different from 327 bearings). Then, ABSOLUTELY, POSITIVELY IT IS ESSENTIAL TO MODIFY THE BOLT HOLES FOR THE MAIN CAP BOLTS TO THE 69-LATER BLOCKS!!!!!. Also, if desired, aftermarket 4-bolt caps could be added (yes, it's more money, but it can be done).
TWO
Buy and aftermarket (Scat, Eagle, etc) 383 crank (3.75 stroke with 350 size main journals) and have the main journals turned down to small journal size------------------------------NOT THE BEST OPTION, BUT IT WILL WORK. Again, modify the bolt holes for the longer 350 style main bolts.
BOTH options above will require notching the bottom of the cylinders for rod clearance. ANY experienced machine shop that does machining on small blocks will do this.
Also, I'm a big advocate of installing a windage tray-----------------------even on a granny grocery getter engine.
The TF heads would be great with a 350 but may be small for a 383. I used them on a 327 last year and picked up 40 rwhp by changing the heads and a roller cam. See my thread Roller Cam for more details. Also check out the thread by Trick Flow on these heads on this forum and the C3 forum. They made 430 gross hp with a crate 350 and a cam change. You may want to consider a 68 Z/28 intake and using ported exhaust manifolds.
So after making these mods I lost my engine to a cracked block last summer. I am now running a Blueprint 383/430.
Thanks for some great info. Lots of decisons to make and spend some money.
MarkC,
Yep figured as much on the trick flow heads. I already have a L79 manifold (as well as a Holley 2818-1 and the L79 Air Cleaner), I know not as good as the Z28 manifold but at least a good starting point for setting a base. This will be a simple street engine so looking for simple power. Nothing elaborate. Trying to stay old school with some simple tech update.
On my current engine in the car now I am running an Edlebrock 2101 and Holley 650 DP. Fits perfectly under the hood and performs awesome.
A couple of more things to do on a small journal, 350s are already like this. I open up the oil passages above the cam bearings. They are 3/16" from the factory and I drill them to 1/4". This is nothing but an internal restrictor. I drill the main bearings to match and chamfer them good. The bottom pic is not clear but I show how much it increases the hole diameter. When you are feeding the main and 2 rods from each hole this is not a good place for a restrictor.
Ahhh! Another engine build thread. Kinda makes this forum one of the best for the sbc hot rodder.
So the scratched up pistons and cylinders suggestes a long time unused motor that was run with corrosion particles in the cylinders. Really just spilled milk now.
So for stroking the motor I recommend slowing down here and crunching numbers for the compression you want with the heads and pistons you want and last the cam you want. It does take time but goes faster and gets more accurate the more you crunch numbers for the combination you want.
What I'm getting at is you need a piston to match the cylinder heads to get the c.r. you target. Well the more you stroke the motor the larger the piston dish you end up with (and many times the more expensive those pistons are). Now there are 327 pistons with 0.080" overbore on the shelf which should be something to keep in mind.
The combinations for the sbc are nearly endless so take your time and have fun with it instead of frustration.
More to come.
Originally Posted by smacota1
I took a few photos tonight. I am sure the machine will give an opinion but wondering what some of you think about this cylinder wear. Could be normal as each cylinder shoes the same pattern.
I also included some pics of the pistons, while they look good they do seems to have a stipple type pattern on the skirt. Don't ever remember seeing this before, but it has been many many years since I have done any of this type work so I am learning again.
06-23-2019, 08:29 PM
Dropping off 1965 327 "3782870" at Machine Shop
